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Testing · head to head

Eppo vs k6

Eppo logo

Eppo

Testing

Warehouse-native experimentation and feature flagging, now sold as Datadog Experiments

From
On request
Rated
-
Full reviewWebsite
k6 logo

k6

Testing

Load testing tool with JavaScript tests on a Go runtime, now owned by Grafana Labs

From
Free
Rated
-
Full reviewWebsite

The short version

  • Only k6 has a free tier, so it costs nothing to try first.
  • Each has a real cost: Eppo datadog acquired Eppo in May 2025 and is folding it into Datadog Experiments, so you are now buying a component of an observability suite rather than an independent product, and roadmap priorities will follow Datadog’s bundle strategy.; k6 tests run on a JavaScript engine embedded in Go rather than on Node.js, so npm packages, Node built-ins and existing shared test utilities generally do not work without being bundled to plain JavaScript, and often not even then.
  • They diverge on capability: Eppo covers Warehouse-native analysis, k6 covers JavaScript test scripts.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which Eppo and k6 actually diverge.

Attributes where Eppo and k6 differ
AttributeEppok6
Starting priceOn requestFree
Pricing modelquoteOpen source, no licence fee
Free tierNoYes
PlatformsWeb, CloudWindows, macOS, Linux, Docker, Kubernetes

Identical on both: user rating (Not yet rated), category (Testing).

What each one covers

Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.

Only in Eppo

  • Warehouse-native analysis
  • Sequential testing
  • CUPED variance reduction
  • Feature flagging
  • Metric governance
  • Contextual bandits
  • Experiment scorecards
  • Heterogeneous effect analysis

Only in k6

  • JavaScript test scripts
  • Thresholds and checks
  • Protocol coverage
  • Browser module
  • Executors
  • xk6 extensions
  • Metrics output
  • Kubernetes operator

What people use each for

The jobs each tool is most often brought in to do.

Eppo

  • A company whose experiment results have repeatedly disagreed with the analytics team’s own numbers because the two systems define revenue differentlynot k6
  • A product organisation with low traffic on a key surface that needs variance reduction to reach a decision in weeks instead of monthsnot k6
  • A team that must keep user-level event data inside its own warehouse for regulatory reasons and cannot ship it to a third-party analytics vendornot k6
  • An existing Datadog customer consolidating product analytics, feature flags and experimentation onto one vendor agreementnot k6

k6

  • Gating a deployment pipeline on a threshold such as 95th percentile latency under a defined arrival ratenot Eppo
  • Generating tens of thousands of requests per second from a small number of machines without a load generator fleetnot Eppo
  • Testing gRPC and WebSocket services with the same tooling and thresholds used for HTTP endpointsnot Eppo
  • Correlating a load test against existing dashboards for an organisation already running Grafana and Prometheusnot Eppo

Where each one falls short

Documented limitations, not opinions. Every one is a constraint you would hit in normal use.

Eppo

  • Datadog acquired Eppo in May 2025 and is folding it into Datadog Experiments, so you are now buying a component of an observability suite rather than an independent product, and roadmap priorities will follow Datadog’s bundle strategy.
  • No pricing is published anywhere, before or after the acquisition; the site offers only a demo request, so cost cannot be estimated without a sales process and is likely to be quoted alongside a wider Datadog contract.
  • Because analysis runs in your warehouse, Eppo shifts compute cost onto your Snowflake or BigQuery bill; a large experiment programme with frequent recomputation raises a line item that does not appear in the Eppo quote at all.
  • Results are only as fresh as the pipeline feeding the warehouse, so teams used to near-real-time dashboards from an event-based tool will wait hours for updated numbers, which slows down the fast iteration loops some product teams rely on.
  • It assumes a mature data stack with a warehouse, defined metrics and analysts who can maintain them; an organisation without that has to build the data foundation first, which makes the real adoption cost far larger than the licence.

k6

  • Tests run on a JavaScript engine embedded in Go rather than on Node.js, so npm packages, Node built-ins and existing shared test utilities generally do not work without being bundled to plain JavaScript, and often not even then.
  • The open source binary runs on a single machine, so distributed load requires the Kubernetes operator or the cloud service, and the operator is infrastructure your team has to run and debug.
  • The AGPL-3.0 licence on the core requires legal review at any company that intends to embed k6 in a product it distributes or offers as a service, which is a slower path than a permissively licensed tool.
  • There is no result storage in the open source tool, so trend history means standing up Prometheus, InfluxDB or Grafana Cloud before load testing produces anything comparable over time.
  • Since the Grafana Labs acquisition the roadmap serves the Grafana observability stack, so a buyer choosing k6 as a standalone tool should expect the standalone experience to receive less investment than the cloud and dashboard integration.
  • Grafana Cloud billing is by virtual user hour, so a long soak test at modest concurrency costs far more than its peak load suggests, and cost planning has to be done in virtual user hours rather than in test runs.

Pricing, plan by plan

Eppo

On request
  • Eppo, now Datadog Experiments$undefined/year
    • Warehouse-native experiment analysis
    • Feature flagging and assignment
    • Sequential testing and CUPED variance reduction

k6

Free
  • k6 OSSFree
    • AGPL-3.0 licence
    • Full test engine, no virtual user limits
    • Runs on one machine unless distributed yourself
  • Grafana Cloud free tierFree
    • Includes a monthly allowance of virtual user hours
    • Hosted test results and dashboards
    • Shared with the rest of the Grafana Cloud free tier
  • Grafana Cloud k6$undefined/month
    • Billed by virtual user hours consumed
    • Load generation from multiple regions
    • Retained test history and comparison

Which should you pick?

Choose Eppo if

  • You need warehouse-native analysis.
  • You work on Web, Cloud.
  • You also want sequential testing.
Eppo review

Choose k6 if

  • You need javascript test scripts.
  • You want to start without paying.
  • You work on Windows, macOS, Linux, Docker, Kubernetes.
  • You also want thresholds and checks.
k6 review

Questions people ask

Is Eppo or k6 better?
Neither clearly leads. Eppo starts at On request and k6 at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Eppo or k6?
k6 has a free tier; the other does not. Paid plans start at On request for Eppo and Free for k6.
Does Eppo or k6 run on more platforms?
Eppo runs on Web, Cloud. k6 runs on Windows, macOS, Linux, Docker, Kubernetes.
Can I use k6 for free?
Yes. k6 has a free tier, so you can try it without paying. Eppo starts at On request.
What is Eppo best used for?
Eppo is most often used for a company whose experiment results have repeatedly disagreed with the analytics team’s own numbers because the two systems define revenue differently, a product organisation with low traffic on a key surface that needs variance reduction to reach a decision in weeks instead of months, a team that must keep user-level event data inside its own warehouse for regulatory reasons and cannot ship it to a third-party analytics vendor, an existing datadog customer consolidating product analytics, feature flags and experimentation onto one vendor agreement. Of those, a company whose experiment results have repeatedly disagreed with the analytics team’s own numbers because the two systems define revenue differently and a product organisation with low traffic on a key surface that needs variance reduction to reach a decision in weeks instead of months are not what k6 is typically brought in for.
What can Eppo do that k6 cannot?
Eppo covers Warehouse-native analysis, Sequential testing, CUPED variance reduction, Feature flagging. k6 covers JavaScript test scripts, Thresholds and checks, Protocol coverage, Browser module.

Answered from the vendors’ own pages

Eppo: Is Eppo still a separate product?

It is still sold and supported, but Datadog acquired it in May 2025 and it is branded as Datadog Experiments. Buy it expecting a Datadog product roadmap.

k6: Can I use npm packages in a k6 test?

Usually not. Scripts run on a Go-embedded JavaScript engine with no Node.js runtime, so packages depending on Node built-ins fail and pure JavaScript libraries must be bundled first.

Eppo: What does it cost?

Nothing is published. There is no pricing page, only a demo request, and pricing is now likely bundled into a Datadog agreement.

k6: Is k6 free?

The core tool is free under AGPL-3.0 with no virtual user limits. Grafana Cloud k6 is a paid service billed by virtual user hours, with a free monthly allowance.

Eppo: Does it need a data warehouse?

Yes. Warehouse-native analysis is the whole architecture. Without Snowflake, BigQuery, Redshift or Databricks there is no product.

k6: Does the Grafana acquisition affect the open source tool?

The tool remains open source and maintained, but investment is directed at making it a data source for Grafana, so standalone use is supported rather than prioritised.

Eppo: Does it include feature flags?

Yes. Assignment and measurement come from the same system, which is the main reason teams pick it over pairing a flag tool with a separate analysis tool.

k6: Can k6 replace a browser testing tool?

No. The browser module measures page-level metrics under load, but functional browser testing belongs in Playwright or a similar tool.

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